Self-locking screw



June 17, 1930. HOSKING 1,764,168

SELF LOCKING SCREW Original. Filed April 30, 1928 IN VE N TOR RICH/4R07. f/OSK/NG A TTORNE Y mentary cross sectional shape.

Patented June 17, 1930 UNITED STATES PATENT -orrrct:

RICHARD T. HOSKING, OF WILMETTE, ILLINOIS, ASSIGNOR, BY MESNEASSIGNMENTS, TO SHAKEPROOF LOOK WASHER COMPANY, INCORPORATED, OFCHICAGO, ILLINOIS,

A CORPORATION OF DELAWARE SELF-LOOKING SCREW Original application filedApril 86, 1928, Serial No. 273,805. Divided and this application filedJanuary 4,

I 1929.- serial No. 330,339.

without spoiling it or mutilating the thread in the work.

Therefore, certain modlfications are 1ncluded in the scope of theinvention as claimed herein.

The subject-matter disclosed herein has been divided out of my co-pendinapplication, Serial No. 27 3,805, filed ApriI 30, 1928, which describesand claims the broader aspects of a locking element comprising a springtongue integral with the screw and adapted to clutch, bind or bite thethread of the work into which the screw is inserted. The basic andcharacteristic feature of the spring-like tongue resides in the factthat a biting edge oi the tongue is projected outwardly beyond the wallof the imaginary cylinder that defines the periphery of the screw.

'The resent invention rovides a novel mode 0' attaining the locklngaction of the spring tongue, namely, by twisting the tongue about itslongitudinal axis.

Each of the two kinds of self-locking action above mentioned, moderateor positive, is attained b a modification in the shape and width 0 ,thetwisted tongue. I 7 To produce the less positive action the twistedtongue is made to present a seg- The more positive locking action isattained by cutting away two sides of such a tongue, pro-, ducing asmaller tongue of approximately equal breadth and thickness. Here thelooking efi'ect is produced by the tongues tendency to roll and jam whenit is attempted to turn the screw in the reverse direction.

With the foregoing and certain other objects in view, which will appearlater in the specification, my invention comprises the devices describedand claimed and the equivalents thereof.

In the drawings Fig. 1 is a detail of'the end and side of a"lefthandscrew embodying my invention.

ig. 2 is a similar view of a modified form l separates the screw intotwo tongues or' members 4, 5 that are not of the same size. The smallerof the two segment-shaped tongues is twisted about its own axis so as toproject one of its corners 6 beyond the cylindrical periphery of thescrew.

A screw made in accordance with Fig. 1 is inserted in the threaded holeof a piece of work causing the outwardly projecting toothed edge 6 to besprung back toward its normal position, but the inherent spring tension,due to its having been. axially twisted, imparts a persisting tendencyto project the biting edge 6 outward, causing it to bind and scrape intothe threaded hole of the work. Such biting action produces a lockingeflect adequate for some uses, although the screw can be removed with anordinary screw-driver if sufiicient force is exerted.

In the modified form of'Fig. 2 the tongue is milled or cut away at twoof its sides 7,v 8,

. giving it approximately equal breadth and This tongue is twistedaxially to thickness. project one of its outer threaded edges 9 beyondthe normal circle of the screw.

At the commencement ofithe locking oper ation the ratchet-like or bitingefiect is the same as in the form shown in Fig. 1, but if theeffort toturn the bolt backwardly persists then the spring tongue tends I to rollor rotate about its longitudinal axis and the extremities of itsdiagonal dimensions become wedged between the wall of the work and thewall 10 of the"complemental prong. In this situation the tongue hassubstantially the strut-like positive locking effect attainedto athreaded screw although it will be unin the rolling tooth type of lockwasher equal to its thickness, for the purposes set shown in my PatentNo. 1,419,564. forth. 4

'For purposes of description I have illus- In testimony whereof, I afiixmy signatrated and defined the invention as applied ture.

RICHARD T. HOSKING. 70

derstood to be also applicableto a bolt or threadless cylindrical bar.Such a bar,

formed with the offset spring tongue herein described can be inserted ina cylindrical hole in a piece of work and can be freely rotated in onedirection, but is retarded or locked with respect to rotation in thereverse direction. Thus the absence of bolt threads I does not deprivethe invention of its utility as a locking device to prevent backwardrotation of a bolt.

Having thus described my invention, what I claim and-desire to secure byLetters Patent is: y

1. A bolt member adaptedto be received in a complemental hole in apieceof work and formed with a slit located at one side of the axial line ofthe bolt and extending lengthwise from an end thereof and defining aspring tongue of relatively small cross sectional area, the free end ofthe tongue twisted axially to provide an ofiset portion which presentsto the work a longitudinal edge that normally projects beyond thecylindrical periphery of the screw to engage the work in lookingrelation, for the purposes set forth.

2. A bolt member adapted to be received in a complemental hole in apiece of work and formed with aslit extending lengthwise from an endthereof and providmga spring tongue formed to substantially rectangularcross sectional shape, the tongue twisted.

axially to produce an offset portion whereby there is presented to thework a biting edge" that normally rojects beyond the cylindricalperiphery o the bolt, to engage the work in looking relation by thestrut-like action of its diagonal dimension, for the purposes set forth.

3. A threaded bolt member adapted to be received in a complemental hole1n a piece of work and formed with a slit extending lengthwise @from anend thereof and defining a spring tongue, the free end". of the tonguewarped, by axial twisting, out of concentricity with the body of thescrew to present-to the work a longitudinal biting edge that normallyprojects beyond the cylindrical periphery of the thread to engage thework in looking relation, for the purposes set forth.

4. In self-locking screws or bolts a bifurcated body at least one branchof which con- ,stitutes a resilient tongue displaced in a mode topresent, outside the perimeter of the body, one of its edges as a bitingedge, the sides of the tongue being cut away, making the width of thetongue substantially

